WEBVTT 00:00.670 --> 00:01.150 Hi everyone. 00:01.150 --> 00:02.410 Welcome back to this tutorial. 00:02.410 --> 00:09.700 In this tutorial we will code and learn how to debug a stream API and what gets passed between the stream 00:09.700 --> 00:10.630 operations. 00:10.660 --> 00:16.750 I'm going to open the example which we coded in one of the previous tutorial, which is streams example. 00:17.140 --> 00:18.100 Let's click on that. 00:18.100 --> 00:26.020 So if you take a look at this example, we are performing one, two and three stream operations and 00:26.020 --> 00:28.390 I'm going to run this example first and check the result. 00:29.350 --> 00:33.370 The result is the name and the students activities. 00:33.370 --> 00:34.820 That's what we are printing here. 00:34.840 --> 00:40.060 Now we want to see what is being parsed from the stream method to the filter method. 00:40.210 --> 00:46.390 There is a handy method that is available as part of the stream API, which is the called peek. 00:47.000 --> 00:51.040 So if you take a look at the peak, peek accepts a consumer. 00:51.130 --> 00:53.770 We all know consumer by now. 00:53.770 --> 00:58.690 Consumer accepts an input and which doesn't return any output. 00:58.810 --> 01:01.360 So now what I'm going to do, I'm going to build a consumer. 01:01.360 --> 01:02.740 Let's create the lambda. 01:03.250 --> 01:07.640 So have the lambda created and it is going to take student as an input. 01:07.660 --> 01:10.840 As soon as I typed in the student, it gave me this recommendation. 01:10.840 --> 01:11.980 I'm going to press enter. 01:12.010 --> 01:12.640 There you go. 01:12.640 --> 01:14.380 We have the lambda created. 01:14.680 --> 01:17.410 To open the curly braces. 01:17.410 --> 01:19.360 And in here, what I'm going to do. 01:19.390 --> 01:20.140 I'm going to. 01:21.470 --> 01:22.220 Rent the student. 01:23.260 --> 01:25.810 For this in presentation mode, the code will be clear. 01:27.550 --> 01:28.030 There you go. 01:28.030 --> 01:35.410 So we have this pick method and then we have the consumer parsed as part of the pick method, as an 01:35.410 --> 01:37.090 input to the pick method actually. 01:37.090 --> 01:39.940 And then we are printing the student in here. 01:39.940 --> 01:42.520 What I'm going to do, I'm going to run and then check the result. 01:43.900 --> 01:44.830 As soon as you run it. 01:45.370 --> 01:48.730 You see, earlier we were just printing the result, which is a map. 01:48.820 --> 01:49.960 We take a look at it now. 01:49.960 --> 01:56.920 It is printing all the values as you see it is printing all the students which are being parsed as part 01:56.920 --> 01:57.370 of the student. 01:57.370 --> 01:58.420 How many students are there? 01:58.420 --> 02:01.000 One, two, three, four, five, six. 02:01.000 --> 02:02.230 There are six students. 02:02.500 --> 02:09.280 Our collection, our student database, get all students also has six students, as you see here. 02:09.460 --> 02:10.390 Student one to. 02:10.390 --> 02:12.350 Student six That's good. 02:12.370 --> 02:18.310 Now we want to see how many students are getting filtered and then passed to the next level in this 02:18.310 --> 02:19.210 student predicate. 02:19.240 --> 02:24.910 So in this student predicate, basically we have the filter which is equal to greater than or equal 02:24.910 --> 02:25.570 to three. 02:25.660 --> 02:32.770 Let's write the peak method and then see how many students are getting passed from this filter to this 02:32.770 --> 02:33.460 filter. 02:33.820 --> 02:35.230 So I'm going to have. 02:36.050 --> 02:39.320 This one printed as after first filter. 02:42.500 --> 02:45.410 Then I'm going to run this example. 02:45.410 --> 02:49.730 Now let's see how many occurrences of this is printed in the console. 02:51.090 --> 02:55.530 I am expecting for because we have like two students in each grade. 02:55.530 --> 02:59.820 We have two, three and four four grades as part of the. 03:00.630 --> 03:01.830 It all students with it. 03:01.950 --> 03:02.630 We take a look at it. 03:02.640 --> 03:03.180 Second grade. 03:03.180 --> 03:06.870 We have two students, third grade, we have two students and fourth grade. 03:06.870 --> 03:08.130 We have two students. 03:08.400 --> 03:14.040 Basically, with this filter going to just print four students, go ahead and take a look at it. 03:15.390 --> 03:16.830 So here. 03:19.020 --> 03:20.850 One, two, three, four. 03:20.880 --> 03:23.700 It gave me four values in the result. 03:23.700 --> 03:30.330 Meaning it printed it, applied the filter, and then it filtered out two students from this actual 03:31.410 --> 03:34.560 students method which returned you six students. 03:34.590 --> 03:40.950 Now what I'm going to do, I'm going to add this peek method here to and then see here I'm going to 03:40.950 --> 03:43.800 name this one as after second filter. 03:44.980 --> 03:46.300 After the second filter. 03:46.330 --> 03:50.410 Let's see how many students are going to be passed from this level to the collector. 03:51.570 --> 03:52.440 And thus. 03:57.000 --> 03:58.470 Bring it up a little bit. 03:58.980 --> 03:59.840 Search for it. 03:59.850 --> 04:02.040 We have like three matches here. 04:02.070 --> 04:03.270 This is what is happening. 04:03.270 --> 04:11.220 So it is applying the second filter, which eventually resulted in passing three students to the. 04:12.730 --> 04:14.410 Actual collector. 04:14.410 --> 04:19.510 And if you take a look at it, it's not just like the whole collection. 04:19.510 --> 04:20.740 It is in sequence. 04:20.740 --> 04:23.080 So first filter and then the second filter. 04:23.080 --> 04:24.910 First filter and then the second filter. 04:24.910 --> 04:27.910 So it applies the filters to the elements one by one. 04:27.910 --> 04:30.940 Basically stream is parsing the elements. 04:32.340 --> 04:38.040 Stream is parsing the elements from the top to the bottom one by one, and it is applying the filter 04:38.040 --> 04:39.960 on the elements one by one. 04:41.140 --> 04:49.210 So this is the way we can debug and then see what is being passed from one operation to the other operation. 04:49.340 --> 04:51.550 So the method is called the peek method. 04:52.150 --> 04:54.290 With this we came to the end of this tutorial. 04:54.310 --> 04:55.360 Thank you for watching.